I don't think so...there's some people that have had speakers for a loooonnnnggg time....they don't just fall to pieces one day. People don't just say "Oh well, they're in pieces now...better get new ones."

I was just reading the Music Direct paper catalog -- my brother recently ordered a CD from them. If you order cables from them, you can ask them to burn them in for you on their cable burn-in machine. It's a free service!!

It is not uncommon for something to require a break in period, but not actually break down.. Take the guitar.. The top surface, with the sound hole, does break in over time.. (And sounds better as it does) It does not break down though..
The fine layer of wood actually flexes with the vibrations caused by the sound waves.. This flexing works on the grain in the wood, and in time, the sound will mellow.. A desirable effect.. This can be applied to most all wooden string instruments..
A guitar sitting in a case, even it was 100 years old, has not aged.. Its just an OLD guitar..
This process will continue the entire life of the instrument, as long as it is played.. It does not damage it..
I don't have the figures on the number of vibrations per second on this, but you all get the idea..